Pressure-assisted toilet flush cartridge

ABSTRACT

A pressure assisted toilet flush cartridge that reduces noise output by controlling water flow. One aspect of the noise reduction is to reduce the initial discharge increase in flow rate. Another aspect is to create a vortex in discharge water to reduce cavitation and quiet the discharged water flow through the bowl.

TECHNICAL FIELD

The present invention relates to a pressure assisted toilets, and morespecifically to a flush cartridge for a pressure assisted toilet.

BACKGROUND OF THE INVENTION

A pressure assisted toilet system typically includes a vessel, a supplysystem and a flush cartridge. The supply system typically includes abackflow prevention and a pressure regulator to ensure that the vesselis maintained below a desired pressure. Since the vessel is fullysealed, it retains the supply pressure after each flush cycle refill.This supply pressure, typically 45-55 psi, pressurizes the pressure tankto its prescribed level and provides a motive force for a subsequentflush of a toilet bowl. Prior art pressure assisted toilet systems arefound in U.S. Pat. Nos. 4,223,698, 5,361,426, and RE37,921 thedisclosures of which are hereby incorporated by reference in theirentireties.

FIG. 1 illustrates a prior art pressure assisted toilet system 20.System 20 is typically encased in an outer vitreous china housing 22, avessel 24 having a discharge outlet 28 and an inlet 30, and a flushvalve cartridge 36. Flush valve cartridge 36 includes a flush valve 38having a seal 40, a top flange 42, and an escape hole 44 formed therein,a flush valve enlargement 46 interposed through and sealing with theescape hole 44, and a flush valve spring 48. Seal 40 of flush valve 38seats against discharge outlet 28 in order to allow pressure tank 24 tofill with water. When ready to be flush, upper chamber 47 contains bothwater and air compressed by the pressure To flush system 20, anactuation lever urges valve enlargement 46 downward, which permits water(and air) to flow through escape hole 44, thereby reducing the pressureabove flush valve 38 within cartridge 36. With this pressure reduced,flush valve 38 is forced upward by the pressure differential createdbetween the tank 24, and the area above the flush valve. As the flushvalve lifts, water is discharged through discharge outlet 28.

A disadvantage of the prior art pressure assisted toilet system is thatthe noise generated during flushing has restricted its use inresidential applications where excessive noise is undesirable. Thisnoise is partially due to the rapid change in water flow rate,cavitation, and flow direction. Additionally, multiple parts arerequired to flush prior art toilets, thus adding to the expense of thesesystems. What is needed, therefore, is a pressure assisted toilet systemthat controls the flow of water such that noise is reduced to moreacceptable levels.

SUMMARY OF THE INVENTION

The present invention relates to reducing the noise output of a pressureassisted toilet. The inventor has found that reducing the rate ofinitial water flow during a flush and swirling the water discharge fromthe pressure tank to the bowl individually reduce undesirable noise, andthat a combination of these two reduce noise even further when comparedto units such as, for example, the U.S. Pat. No. 4,223,698 Patent.

An embodiment of the pressure assisted toilet flush cartridge includes agenerally cylindrical housing having a top end, a bottom end, aninternal surface and a discharge aperture having a first predeterminedarea. The cartridge further includes a flush valve interposed within thehousing and having a top flange, a generally conical hollow body with atop flange opening, and a lower extension, where the flange and theinternal surface define a generally annular gap having a secondpredetermined area, and where the first predetermined area is largerthan the second predetermined area.

Another embodiment of the present invention provides a flush valve for apressure assisted toilet that includes a top outer edge circumscribing apredetermined area, a flush valve seal selectively in sealing contactwith a vessel outlet and a generally hollow body connecting the topouter edge and the valve seal. The body has an opening and contains apredetermined volume of water, where the volume of water provides amotive force to assist reseating the flush valve seal to seat with avessel outlet.

A further embodiment includes method of reducing noise in a pressureassisted toilet that includes imparting a swirling effect in a fluiddischarged from the pressure tank to create a vortex.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a sectional elevation view of a prior art pressure assistedflush system including the flush cartridge.

FIG. 2 is a similar sectional elevation view as in FIG. 1 except that aflush cartridge in accordance with an embodiment of the presentinvention has replaced the prior art version

FIG. 3 is an enlarged partial sectional elevation view of the flushcartridge of FIG. 2.

FIG. 3A is an enlarged sectional elevation of the flush cartridge ofFIG. 2.

FIG. 3B is an enlarged sectional elevation view similar to FIG. 3A,illustrating an alternate embodiment of a portion of the flushcartridge.

FIG. 4 is a sectional view of a conceptual actuator cartridge for theflush cartridge of FIG. 2.

FIG. 5 is a graphical depiction of flow/volume results of a prior artflush cartridge.

FIG. 6 is a graphical depiction of flow/volume results of an embodimentof a flush cartridge of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 2 illustrates a pressure assisted toilet flush system 70 inaccordance with an embodiment of the present invention. The system 70includes a vessel, or pressure tank, 74 having a discharge outlet 78 andan inlet 80, and a flush cartridge 82. Discharge outlet 78 is preferablydefined in part by a frusto-conical interior surface 84 and a generallycylindrical surface 86, as discussed below.

With reference to FIGS. 2 and 3, flush cartridge 82 includes a jacket,or outer housing, 88, a flush valve 90, and a top cap 92. Outer housing88 includes a cylindrical body (or jacket) 94 that extends from a topend 96 to a bottom end 98, and an internal surface 100. Top end 96defines a larger inside diameter than bottom end 98, and internalsurface 100 is accordingly tapered from top end 96 to bottom end 98.Internal surface 100 includes a retaining element 104 disposed thereonand extending inwardly from the internal surface 100. Preferably,retaining element 104 is three equally spaced retaining lugs formed onthe internal surface during forming of outer housing 88.

The flush valve 90 includes a seal retaining portion 108, a seal 110, atop flange 112, a generally hollow frusto-conical body 114 extendingtherebetween, a lower portion 116 extending below the seal 110, and atop flange opening 120 that extends from body 114 past top flange 112,thus providing a hole for filling body 114 of flush valve 90, asdiscussed below. Preferably, seal 110 is a conventional o-ring that isrestrained within seal retaining portion 108 and extending radiallytherefrom in sealing contact with discharge outlet 78 when flush valve90 is closed, as discussed in greater detail below. Top flange 112includes a top outer edge 118 that defines a predetermined area.

A generally annular gap 122 is located between top outer edge 118 andinternal surface 100. Gap 122 increases slightly as flush valve 90 riseswithin outer housing 88 due to the taper of internal surface 100. Gap122 allows fluid to pass from pressure tank 74 to flush cartridge 82, asdiscussed below.

Lower portion 116 is illustrated with a helical groove 126 formedtherein. Helical groove 126 is illustrated with a semi-circular section,although any suitable section may be formed on lower portion 116. Theeffective width, W of helical groove 126 increases as helical groove 126extends away from seal retaining portion 108. As best seen in FIG. 3,helical groove 126 has an effective width W1 at the end closest to sealretaining portion 108. Helical groove 126 has an effective width W2 atabout the midpoint of helical groove 126 and an effective width W3adjacent the end that is opposite seal retaining portion 108. W3 isgreater than W2, which is greater than W1. Preferably, W3 is about 50%greater than W1. Varying the size of the semi-circular passages ofhelical groove 126 varies both the effective area of gap 124 and theinitial discharge flow rate and thus varies the rate of lift and thecircularity of water into the bowl adjacent generally cylindricalsurface 86, as discussed below. With reasonable extremes, the morecircularity, the greater the flow noise reduction.

While body 114 is described as being frusto-conical shaped, body 114 maybe any suitable shape that retains fluid and connects top flange 12 toseal retaining portion 108. Flange opening 120 allows water to enterbody 114 while body 114 retains the water to provide a downward force(illustrated as D in FIGS. 2 and 3). Top cap 92 includes a toppassageway 130 extending there through and connecting outer housing 88with an actuation port 132. The actuation of flush valve 90 viaactuation port 132 is discussed with reference to FIG. 4, below.

With specific reference to FIG. 3A, a generally annular gap 124 islocated between generally cylindrical surface 86 and lower portion 116adjacent width W1 of helical groove 126. Gap 124 allows water to travelfrom pressure tank 74 to the bowl (not shown). Gap 124 controls thedischarge flow rate from pressure tank 74 as discussed in greater detailbelow.

The area of passageway 130 (FIG. 3) is greater than the combination ofthe area defined by gap 122 (FIG. 3) and the area defined by gap 124(adjacent width W1, FIG. 3A). Preferably, the area of passageway 130 isat least 20% greater than the combination of the area defined by gap 122and the effective area defined by gap 124.

FIG. 3A illustrates the lower portion 116 of FIG. 2 with helical groove126. FIG. 3B illustrates an alternate embodiment where a lower portion116′ includes a helical protrusion 126′. Helical protrusion 126′ createsan outwardly extending fin that imparts a swirling effect within thewater discharged from pressure tank 74

FIG. 4 illustrates a simple actuator assembly 140. Actuator assembly 140includes an actuator body 142 having an inlet 144, an outlet 146, acylindrical interior surface 148, and an endcap 150. Endcap 150 has aplunger 152 extending there through and connects an actuator handle 160with a grommet seal 162. Plunger 152 has an elastomeric cup seal 164attached thereto with a return spring 166 extending between. Actuatorhandle 160 is rotatable with respect to plunger 152 via pin 170.Actuator handle 160 includes an actuation surface 172 that defines agenerally equiangular spiral. That is, actuation surface 172 is curvedsuch that distance H is greater than distance G. Inlet 144 is in fluidcommunication with the actuation port 132. Outlet 146 is open to theatmosphere within china housing 72 or can be connected to the vessel'soutlet below seal 110. While actuator assembly 140 can be made of anysuitable material, acetal plastic would be preferred.

When installed, system 70 is filled with water through inlet 80. TheAmerican National Standard mandates that the typical residential waterpressure range between 20 psi to no more than 80 psi. Preferably, apressure relief valve (not shown) is located in the water line between awater source and inlet 80 to restrict inlet water pressure to thedesired pressure (usually around 25 psi). After filling, vessel 74 ispressurized to the inlet water pressure setting. This tank pressureurges seal 110 into a binding contact with discharge outlet 78 andgrommet seal 162 into a binding contact with outlet 146. Since air iscompressible and water is not, as vessel 74 refills after being flushed,the air within the vessel 74 and flush cartridge 82 is compressed intoflush cartridge 82. During the first fill, some water will pass throughgap 122 and enter body 114. When the pressure within vessel 74, flushcartridge 82, and actuation assembly 140 equalize, flow into theassembly ceases.

In operation, an operator rotates actuation handle 160 such that grommetseal 162 is unseated from outlet 146. This releases compressed fluidfrom actuator assembly 140 and outer housing 88 such that the pressureabove flush valve 90 is reduced and falls below the pressure withinvessel 74. The pressure above flush valve 90 falls below the pressurewithin vessel 74 because the area of passageway 130 is greater than thearea defined by gap 122 plus the area defined by gap. The relationshipbetween outlets 130 and 146 to gaps 122 & 124 is critical because iftheir combined area is too close to equal, the flush valve's lift willbe restricted causing an insufficient discharge flow rate to causeproper extraction of the water closet bowl. fluid released throughoutlet 146 flows into the china housing (not shown) and eventuallythrough a drain passageway into the water closet bowl.

The greater pressure below flush valve 90 causes flush valve 90 to rise.When flush valve 90 rises, seal 110 unseats from discharge outlet 78,thereby permitting water from vessel 74 to escape through dischargeoutlet 78. After the majority of water within pressure tank 74 hasdischarged through discharge outlet 78, thereby reducing the pressurewithin pressure tank 74, flush valve 90 falls due to the force ofgravity and seal 110 reseats on discharge outlet 78. Because the waterwithin body 114 of flush valve 90 is retained, this creates an extraforce that ensures that the flush valve falls, or returns to a seatedposition. Flush valve lower portion 116 ensures that the flush valve 90remains centered for proper seating and sealing. As pressure tank 74refills, pressure within pressure tank 74 increases, thereby ensuring aproper seat between seal 110 and discharge outlet 78, and grommet seal162 and outlet 146.

Helical grooves 126 divert the water flowing through gap 124 into aswirling pattern, or vortex, as a portion of the flowing water flowswithin each helical groove 126. As flush valve 90 begins to lift fromits seat on surface 84, a limited amount of water is allowed to flowthrough discharge outlet 78 as the effective area defined by gap 124 islimited by dimension W1 of helical grooves 126 and the clearance betweensurface 86 and lower portion 116. As flush valve 90 continues to rise,the effective area defined by gap 124 increases as the width of helicalgrooves increase, thereby permitting greater flow. This characteristicof flush valve 90 results in a gradual increase in flow of water throughdischarge outlet 78 as flush valve 90 rises.

As best seen in FIG. 5, a prior art flush valve, such as the flush valvedisclosed in U.S. Pat. No. 4,223,698, without a helical groove formed ona lower portion, and installed on a major manufacturer'spressure-assisted bowl permits an initial spike in discharge flow thatresults in a maximum discharge flow of 57 gpm within 0.1 second afterflushing. Of special interest is that the initial increase in flow rateof water discharged spikes as the flush valve is opened. At a tank testpressure of 50 psi and background noise level of 40 db, the operationillustrated in FIG. 5 was measured at 84.2 db.

FIG. 6 illustrates a similar flush valve with helical groove 126 formedon a lower surface extending through the discharge outlet 78 when theflush valve 90 is in the unseated position to restrain the maximumdischarge flow to 46 gpm at approximately 0.2 seconds after flushing.When compared to FIG. 5, the initial increase in flow rate is moregradual, thereby reducing the flow noise. This gradual increase in flowrate is due, at least in part, to the width W1 of helical groove 126being less than the width W3. Since the width W1 makes the effectivearea of gap 124 less as the flush valve 90 begins to rise, the volume ofwater permitted through discharge outlet 78 in about the initial secondof flow is less than the volume of water permitted. Also, because of thechanged relationship between inflow and outflow areas, the duration ofdischarge above 20 psi is extended, thus allowing improved extractioncapability. At a water supply test pressure of 50 psi and backgroundnoise level of 40 db, the operation illustrated in FIG. 6 was measuredat 78.0 db. The graphical representations of FIGS. 5 and 6 illustratethat the initial increase in flow rate of water discharged and existenceof backpressure affect noise levels.

Additionally, the vortex imparted into the flow illustrated in FIG. 6reduces cavitation immediately past the lower portion 116 as thepressure is reduced due to the increase in area for water flow, therebyreducing noise. Also, the vortex flow through the inner areas of thebowl (not shown) reduces noise associated with normal pressurized waterflow through a pressure assisted toilet bowl.

While the invention has been described with respect to specific examplesincluding preferred modes of carrying out the invention, those skilledin the art will appreciate that there are numerous variations andpermutations of the above described systems and techniques that fallwithin the spirit and scope of the invention as set forth in theappended claims. Specifically, bowl tolerances and hydraulic designs mayeffect the overall noise levels during a flush.

1. A mechanism for initiating a flush of a pressure assisted toilet,comprising: a generally cylindrical housing having a top end, a bottomend, an internal surface and a discharge aperture having a firstpredetermined area; a flush valve interposed within said housing andhaving a top flange, a generally hollow body with a top flange opening,and a lower extension, wherein said flange and said internal surfacedefine a generally annular gap having a second predetermined area, andwherein said first predetermined area is larger than the secondpredetermined area.
 2. The mechanism of claim 1, wherein said flushvalve further comprises a flush valve seal selectively in sealingcontact with a pressure tank outlet.
 3. The mechanism of claim 2,wherein said hollow body selectively contains a predetermined volume ofwater, and wherein said volume of water provides a motive force toassist said flush valve seal to seat with the pressure tank outlet. 4.The mechanism of claim 2, wherein said lower extension selectivelyextends through the pressure tank outlet.
 5. The mechanism of claim 1,wherein said housing further comprises a retaining element disposed onsaid internal surface, wherein said retaining element interferes withsaid top flange to prevent said flush valve from undesirably passingthrough said bottom end.
 6. The mechanism of claim 1, wherein saidwherein said lower extension has a generally helical muffler surface. 7.The mechanism of claim 6, wherein said generally helical muffler surfacecomprises a helical groove formed within said lower extension.
 8. Themechanism of claim 1, wherein said lower extension imparts a vortex influid flowing past said lower extension.
 9. The mechanism of claim 1,wherein said flush valve is actuated by a decrease in pressure withinsaid housing.
 10. A flush valve for a pressure assisted toilet,comprising: an edge circumscribing a first predetermined area; a flushvalve seal selectively in sealing contact with a vessel outlet; agenerally hollow body connecting said edge and said valve seal andhaving an opening, wherein said hollow body selectively contains apredetermined volume of water, and wherein said volume of water providesa motive force to assist said flush valve seal to seat with a vesseloutlet.
 11. The flush valve of claim 10, further comprising a lowerextension, wherein said lower extension has a generally helical mufflersurface.
 12. The flush valve of claim 11, wherein said generally helicalmuffler surface comprises a helical groove formed within said lowerextension.
 13. The flush valve of claim 11, wherein said generallyhelical muffler surface comprises a helical fin extending from saidlower extension.
 14. The flush valve of claim 10, wherein said flushvalve is selectively interposed within an outer housing of a flushcartridge, the flush cartridge including a passageway of a secondpredetermined area, said edge and an internal surface of the outerhousing define a generally annular gap having a third predeterminedarea; wherein a lower portion of said flush valve is selectivelyinterposed within a discharge outlet, said lower portion and thedischarge outlet defining a gap having a fourth predetermined area; andwherein the second predetermined area is greater than the combination ofthe third predetermined area and the fourth predetermined area.
 15. Theflush valve of claim 10, wherein said lower extension creates a vortexin fluid flowing past said lower extension.
 16. A method of reducingflushing noise in a pressure assisted toilet, wherein the pressureassisted toilet includes a pressure-assisted tank, the methodcomprising: imparting a swirling effect in a fluid discharged from thepressure tank to create a vortex.
 17. The method of claim 16, furthercomprising: determining an initial flow rate of water discharged fromsaid pressure tank; and reducing the initial flow rate.
 18. The methodof claim 16, wherein said vortex is created outside said pressure tank.19. The method of claim 16, further comprising: determining the amaximum flow rate of water discharged from said pressure tank; andreducing said maximum flow rate.
 20. The method of claim 16, furthercomprising limiting the initial discharge flow rate from the pressuretank by limiting the effective area for flow of fluid as the fluidbegins to flow.
 21. A flush valve cartridge for a toilet comprising: anouter housing having an internal surface; a passageway having a firstpredetermined area to permit flow of a fluid; and a flush valve at leastpartially interposed within said outer housing, said flush valveincluding an edge and a lower portion, wherein said edge and saidinternal surface define a gap having a second predetermined area, saidlower portion is at least partially interposed within a discharge outletof the toilet, said lower portion and said discharge outlet defining agenerally annular gap having a third predetermined area, and whereinsaid first predetermined area is larger than the combination of saidsecond predetermined area and said third predetermined area.
 22. Thecartridge of claim 21, wherein said lower portion is selectively raisedrelative to the discharge outlet and said third predetermined areaincreases as said lower portion is selectively raised.
 23. The cartridgeof claim 21, wherein said flush valve further comprises a generallyhollow body selectively adapted to fill with a fluid.
 24. The cartridgeof claim 21, further comprising a helical groove formed on said lowerportion.